Gce Model Questions Vol1 2018 Agricultural Science Question 25

Cassava chips are to be dried in a solar dryer. The chips start with a moisture content of 45% (wet basis) and a temperature of \(30^{\circ}\)C. The dryer maintains an ambient temperature of \(45^{\circ}\)C and provides a drying constant \(k = 0.08\ \text{h}^{-1}\) according to Newton's law for moisture ratio: \(MR = e^{-kt}\), where \(MR = \frac{M-M_{e}}{M_{0}-M_{e}}\). The equilibrium moisture content at \(45^{\circ}\)C is 10% (wet basis). The target moisture content is 12% (wet basis).\n(a) Calculate the drying time required to reach the target moisture content.\n(b) If each hour of drying evaporates 0.5 L of water, compute the total water loss.\n(c) The market price of dried chips is \(\text{₦}200\) per kg. Drying incurs a fixed energy cost of \(\text{₦}150\) per batch. Assuming the initial fresh weight is 1000 kg and the dry matter remains constant, determine the profit per kilogram of dried product.